Bo Sundborg

The edges of black holes are puzzling regions whose properties have been intensely debated. I develop tools to probe these regions exactly in theory. Similar tools may also describe edges in time, for example the initial conditions of our universe.

From observations, we know that black holes are common, and their astrophysical and cosmological significance is still unfolding. For instance, it is unknown if the oldest of them have had time to form after the Big Bang, or if they were already present as primordial black holes.

They however raise even more fundamental puzzles on the nature of space and time, by providing a fascinating link between spacetime and thermodynamics. This link focuses on the black hole horizon regions – separating the black hole proper from the outside world – and has led to the concept of "holography". In holography, the Maldacena conjecture, "gauge/gravity duality" or any of its namesakes, local physics on a boundary (like the horizon) is equivalent to gravitational physics inside the boundary.

Some time ago Santa Barbara physicists argued that observers falling through the horizon encounter hot regions, fire walls, in conflict with expectations that nothing dramatic happens. To settle such issues, we need concrete and controllable models combining black holes and quantum mechanics. My research studies such models, using methods from Bose-Einstein condensates and topological field theory via gauge/gravity duality to conformal field theory. Recently, we have established that an exactly soluble model reproduces the most typical black hole features, motivating a closer investigation.